Explosion resisting clock



Jan. 13, 1953 H. BUSH ETAL 2,625,004

EXPLOSION mzsxswms CLOCK Filed April 14, 1948 2 SHEETS-SHEET 1 BYWq WK a it arms Jan. 13, 1953 H. L. BUSH ET AL EXPLOSION RESISTING CLOCK Filed April 14, 1948 IN V EN T013; #22 0244 Ba: lf llvd rZ/E Par-2;)?

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Patented Jan. 13, 1953 UNITED STATES PATENT OFFICE EXPLOSION RESISTING CLOCK Application April 14, 1948, Serial No. 20,966

6 Claims.

lhis invention relates to electrically operated timed clocks, and more particularly to an explosion resisting clock for use in hazardous locations where there are inflammable or explosive materials in the atmosphere.

The invention has as an object a clock of the type described embodying a structure by which the operating motor for driving the clock mechanism is totally enclosed in a flame tight housing, and further embodying a structural arrangement by which the outer casing and the crystal may be quickly and conveniently removed and thereupon the dial and clock works assembly removed, all without interfering or otherwise affecting the flame tight mounting of the actuating motor.

The invention consists in the novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is had to the accompanying drawings in which like characters designate corresponding parts in all the views.

Figure l is a front elevational view of a clock embodying our invention, with parts broken away.

Figure 2 is a sectional view taken on line 2-2, Figure 1.

Figure 3 is a view taken on line 33, Figure 2, showing the driving disk carried by the output shaft of the motor in top plan.

Figure 4 is a plan view of the couplin member carried by the input shaft of the clock works.

Figure 5 is a side elevational view of the structure shown in Figures 3 and 4 for connecting the motor and clock works, with a contiguous portion of the closure of the motor housing in section.

The driving motor I0 is mounted in a housing H formed with one or more internally threaded hubs [2 for connection to a conduit line. One side of the housing H is formed with an opening of considerable dimension, and a closrue I3 is provided for the opening being detachably secured to the housing, as by screws [4.

The motor It is supported by bosses depending from the under side of the cover l3. The output shaft 30f the motor extends through a bushing ll threaded into the closure. The length of the bushing is such as to meet the requirements of a flame tight joint between the bushing and the motor shaft I6. The outer face of the closure is formed with a depression concentric with the bushing.

A plate 20 is detachably secured to the housing, or the closure l3, as by the screws 14, and extends radially outwardly from the housing. The housing is mounted upon a wall surface 2], and the plate 20 serves to hold a cylindrical casing 22 against the wall, the casing being formed with an annular groove 23 to receive a bead 24 formed on the periphery of the plate 20. The plate 20 is also formed with a groove to receive a head 25 formed on the edge of a cylindrical casing 26 which carries the clock crystal 2?. The casing 28 is apertured to receive a strap 28 carried by the plate 20, and the opposite side of the casing is provided with a screw 29, the inner end of which is movable into engagement with an inclined bracket 30 also carried by the plate 23, the strap 23 and screw 29 serving to detachably secure the casing 28 to the plate 20. p

A dial 32 is detachably mounted on the plate 23 and is yieldingly pressed outwardly into engagement with the casing 26. A plurality of spring arms 33 are secured to the plate 23 and are inclined outwardly therefrom. The outer ends of the arms 33 are formed with bent or hook portions 34 positioned in notches 35 formed in the peripheral edge of the dial 32. With this arrangement, the dial is inserted snap-fashion into the arms 33, and when the outer casing 23 is mounted upon the plate 23, the casing engages the dial forcing the same downwardly against the yielding action of the arms.

A clock works, or gear train, is mounted on the rear side of the dial 32 and is enclosed by a cupshaped dust shield 36. The clock works includes an input shaft 31, to the lower end of which is secured a radially extending arm 38. A split ring or annular member 39 is secured to the outer end of the arm 38, as at 40, see Figure 4. The opposite end of the member 39 is bent downwardly to form a depending portion 4 I.

A disk 42 is fixedly secured to the protruding end of the motor shaft [6, and is formed with a plurality of notches 43 extending radially inwardly from the periphery of the disk 42. The endportion 41 of member 39 is arranged to enter into one of the slots 43 when the dial assembly is positioned in the supporting arms 33, as better shown in Figure 5. A cylindrical inverted cupshaped member 44 is secured to the clock works and depends through the dust cylinder 36 and is arranged concentric with the input shaft 31. When the dial assembly is inserted in the supporting arms 33, this member 44 enters a depression formed in the closure I3 and serves thereby to accurately aline the shaft 31 with the motor shaft I6.

The annular split spring member 39 and the notch disk 42 provide means for detachably connecting the motor shaft with the input shaft of the clock works. The member 39 is formed of thin, resilient sheet material, such as spring steel, and shaped in the form of a helix, whereby when the dial assembly is positioned in the arms 33, the depending end portion 41 is yieldingly moved into engagement with the driving disk 3 42. As soon as the motor imparts rotation to the disk 42, the end portion 4| of the split ring 39 will enter one of the slots 43 and thereupon effect rotation of the shaft 31. With this arrangement, the mounting of the dial and clock works carried thereby does not in any way result in injury to any of the operating mechanism of the clock. The clock works is provided with the usual output quill shafts 45 extending through the dial and on the outer ends of which are mounted the clock hands 46.

It will be apparent from 'thedescription that the clock, while embodying the advantageous feature of being explosion resisting,'is convenient to mount, and particularly convenient to disassemble for repair, or replacement.

What we claim is:

l. Anexplosion proof clock comprising a housing having means for connection to a conduit line and having an opening in one side, a flame tight closure for the open side of the housing, a driving motor mounted in the housing and having an output shaft extending through said closure in flame tight relation thereto, a plate extending radially from said housing, a dial detachably secured to said plate in spaced relation -thereto,-=a clock works assembly'carried by said dial and arranged intermediate said plate and dial, said works assembly having output shafts extending through the dial and an input shaft, motion transmitting means connecting said ini put shaft to the output shaft of the motor, a

casing enclosing the dial, means operable externally of the casing for detachably securing the casingto said: plate, and a'crystal carried by said 'casing and overlying the dial.

2. Anexplosion proof clock comprising a housing having meansfor connection to a conduit lineand having an opening in oneside, a closure detachably securedto the open side of the housing in flame tight relation thereto, a driving motor mounted in the'housing and having an output shaft extending through said closure in {name tight relation thereto, a plate mounted on the'closure and extending radially fromthe housing, a clock dial detachably mounted on the plate -inf spaced relation thereto, a clock works carried :by the "dialand arranged intermediate the dial and 'sai'd plate, said works having an input shaft, motion transmitting means detachably connectiiIigf-Said input Shaft With the "output shaft of the "motor, a casing detachably secured to said plate-by'means-operable externally of the casing,

"said casing encircling saiddial, and a crystal carried by said casingand overlying the dial.

'3. An explosion-proo'f-electric clock comprising a "housing having 'means for connection to a conduit-line and having an open side, a closure "forthe open side detachably secured to the housing in flame tight relation thereto, a plate secured to'the closure and extending radially from-thehousing-adieu arranged in spaced relation to the plate ,-aclockworks assembly carried fby the dial and arranged intermediate the -dial'-in*said platexsaid works having output shafts extending through the dial and an input shaft "detachably connected'to the output shaft of said motor, a-easing detachably mounted on the plate, a' crystal carried by the casing and overlying sai'd "dial, and-means'oarried by said plate and cooperable to yieldingly press said dial against 'lsaid c'asing.

4; Anexplosion-proof electric clock compris- '-ing a housing'having"means for connection to a -=conduit line and-beingformed with an open side, a closure for the open side of the housing detachably secured thereto in flame tight relation, a driving motor mounted in the housing and having an output shaft extending through the closure in flame tight 'relation'thereto, a plate detachably secured to said closure and extending radially from the housing, a casing detachably secured to said plate, a crystal carried by said casing, a dial arranged in the casing, a clock works assembly carried by the dial and arranged intermediate the dial and said plate, motion transmitting means detachably connecting said works with the output shaft of said motor, means carried by said plate and cooperable to detachably secure the dial to the plate and to yieldingly urge the dial into engagement with saidcasing.

5. An explosion proof electric clock comprising a housing having means for connection to a conduit line and having an open side, a closure for the open side of the housing detachably secured thereto in flame tight relation, a plate extending radially from the housing, a plurality of yieldable arms mountedon said plate and extending outwardly therefrom, a 'dial plate detachably mounted on said arms, a clock works assembly mounted on the under side of the dial plate and having an input-shaft, a driving motor mounted in the housing and having an output shaft extending through said closure, said closure and said dial plate having means cooperable to position the input shaft of the clock works and the output shaft of said motor in axial alinement, and motion transmitting means detachablyconnecting said shafts.

6. An explosion proof electric clock comprising a housing having means for connection to a conduit line'and having an open side, a closure for the open side of the housing detachably secured thereto inflame tight relation, a motor arranged in the housing and being mounted on said closure and having an output shaft extending therethrough, a supporting plate mounted on said closure and extending radially therefrom, a dial detachably mounted on said plate, a clock works mounted on the under side of said dial and having an input shaft, said-closure being formed with a depression concentric with the output shaft ofsaid motor, said clock works having a sleeve extending into said depression and being operableto position the output shaft of said motor and the inputshaftof said works in axial alinement, and means mounted within said sleeve and operable to detachably connect said shafts.

HAROLD L. BUSH.

WILLARD E. PARISH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

